Does it sound like autism is always a mental impairment?

Yes: To get any diagnosis, by defination there needs to be some level of functional impairment. However, many people with autism spectrum disorders can get adequate help to alleviate functional impairments.

Yes: Autism and related spectrum conditions are definitely neurobiologic conditions impacting brain function. Best evidence indicates a genetic predisposition with an environmental or neurotoxicity trigger.

Not always: Mental retardation, now called intellectual disability, co-occurs in about 45-65% of people with autism. It means overall iq is <70. Mental impairment is a term used as a euphemism for intellectual disability or mental illnesses/psychiatric disorders. People with autism have a higher incidence of mental illness than the general population. Autism is a neurodevelopmental (brain-based) disorder.